preg_replace('~D~', '', $phone);

/^([a-z0-9_.-]+)@([a-z0-9_.-]+).([a-z.]{2,6})$/

/^(https?://)?([da-z.-]+).([a-z.]{2,6})([/w .-]*)*/?$/

<url>(.*)([^/]+)</loc>(.*)</url>

<input type="tel" name="phone" class="form-control form-block" placeholder="+7(999)999-99-99" pattern="[+]d{1}[(]d{3}[)]d{4}[-]d{2}[-]d{2}" value="">

Character	Meaning	Example
.	Matches any single character	– c.t will match cat, cot, cut, etc.
+	Repeats the previous match one or more times – a+ matches a, aa, aaa, etc
*	Repeats the previous match zero or more times. – a* matches all the same things a+ matches, but will also match an empty string.
?	Makes the match optional.	colou?r will match color and colour.
^	Called an anchor, matches the beginning of the string	^a matches a string that begins with a
$	The other anchor, this matches the end of the string.	a$ matches a string that ends with a.
( )	Groups several characters into a single unit, and captures a match for use in a backreference.	(ab)+ matches ababab - that is, the + applies to the group. For more on backreferences see below.
[ ]	A character class - matches one of the characters	c[uoa]t matches cut, cot or cat.
[^ ]	Negative character class - matches any character not specified	c[^/]t matches cat or c=t but not c/t